In the construction of a stub sill, open top gondola or hopper railroad car, assembly difficulties have been encountered in joining the top chords extending along the upper sides of the car to the transversely extending end chords of the car. In addition, assembly difficulties have also occurred in joining the end diagonals of the stub sill car which are required for reacting the overturning component or the coupler loads at the car ends. Still other assembly difficulties have been encountered in joining the side and end sheets at the corners of the car to the top and end chords and to the end diagonals. In the past, this joining work (e.g., welding) has required considerable hand fitting and jigs. Additionally, load paths through the corner connections of prior art railroad cars made from fabricated steel parts were generally discontinuous (i.e., the load paths were comprised of a number of separate parts welded together) and, therefore, did not result in efficient load transfer (i.e., excess structural material was required to ensure that the loads were properly transferred).
Heretofore, steel castings have been used to join the end and side chords of the car. However, these prior art corner castings nevertheless resulted in discontinuous load paths between the end diagonals and the side and end chords. Even with the prior art castings, considerable hand fitting work was required to make the connections between the chords, the end diagonals, and the side and end sheets. In addition to resulting in discontinuous and inefficient load paths, as mentioned above, these prior art designs also varied in load carrying capability from one car to another and were, in some instances, dependent on dimensional variations from car-to-car and the manner in which the various components were hand-fitted during assembly.
Thus, there has been a long-standing need for a structure for an open top gondola or hopper railroad car in which the end and top chords could be efficiently joined together with the end diagonals, and in which the side and end sheets could be secured to the chords and to the end diagonals in a repeated and reliable fashion from car to car.